Conventionally, as described in Patent Literature 1, for example, PTO valve equipment of a working vehicle is well known. With regard to the PTO valve equipment described in Patent Literature 1, a rear end of a rear housing of a vehicle body is covered by a PTO rear cover, and the PTO rear cover supports tips of a brake support shaft of a brake braking a clutch housing of a PTO clutch, a clutch shaft, and a PTO shaft, so as to construct a sub assembly. Accordingly, the sub assembly is built in the vehicle body simultaneously when attaching the PTO rear cover to the rear end of the rear housing.
However, with regard to the PTO rear cover which is attached to power take off equipment of the working vehicle, modularization of the PTO valve equipment is not considered, and switching from a mechanical PTO clutch to a hydraulic PTO clutch is not considered. Since the conventional PTO valve equipment is positioned far from the PTO clutch mechanism, oil pressure is lost in piping and the like between the PTO valve equipment and the PTO clutch mechanism, whereby control pressure of oil is changed and the control is unstable.
On the other hand, with regard to a working vehicle such as a tractor, a forward/rearward travel selector, a high/low speed selector (transmission), and the like is disposed in a clutch housing or a transmission casing (hereinafter, referred to as a vehicle body housing). Among other things, the forward/rearward travel selector is controlled by a forward traveling hydraulic clutch and a rearward traveling hydraulic clutch so as to switch the traveling direction of the working vehicle. The equipment in which valves controlling the operation of the forward/rearward travel selector are inserted is referred to as control valve equipment, and arranging the equipment on one of the sides of the vehicle body housing is known (for example, see Patent Literatures 2 and 3).
With regard to Patent Literatures 2 and 3, construction of the control valve equipment shown in FIG. 19 is disclosed. Namely, the control valve equipment 469 is inserted into an opening 451 in one of side walls of a front housing 401 of a vehicle body housing so as to be fixed to the front housing 401. The control valve equipment 469 comprises a plate member 469a along the outer surface of the side wall of the front housing 401, an outer housing member 469b along the plate member 469a through a thin partition 450, and an inner housing member 469c along the inner surface of the outer housing member 469b, and positioned in the front housing 401.
The plate member 469a is screwed to the outer housing member 469b through the partition 450 by bolts, and the inner housing member 469c is screwed to the inner side of the plate member 469a. With regard to these members, the plate member 469a is used mainly to form an oil passage, and a connection oil passage between the plate member 469a and the outer housing member 469b is formed in the partition 450. An oil passage connecting the oil passage in the plate member 469a to the oil passage in the inner housing member 469c is arranged to face them.
A housing part 469d is formed on the outer side surface of the outer housing member 469b of the control valve equipment 469 a main relief valve 471, which controls the flow rate of pressure oil, and a directional control valve 470 are provided in the housing part 469d vertically with each other and along the longitudinal direction. A relief valve 472, a flow rate control valve 473 and an oil passage shut-off valve 474 are arranged along the longitudinal direction.
Accordingly, the conventional control valve equipment is attached separately from the forward/rearward travel selector and the like, whereby the forward/rearward travel selector can be built in the vehicle body housing easily. Furthermore, the conventional control valve equipment can be fixed to the side wall of the vehicle body housing easily, whereby the control valve equipment itself also can be attached easily.
However, since the valves are arranged laterally, the lateral width of the conventional control valve equipment is large. Furthermore, the equipment comprises plural members, making it difficult to construct the equipment compactly. A vehicle body frame is disposed longitudinally at the lateral center of a platform, and fuel tanks are arranged at left and right sides of the vehicle body frame. Then, the control valve equipment is disposed on one of the side walls of the vehicle body frame so as to be positioned in a gap between the fuel tank and the vehicle body frame. Accordingly, if the lateral width of the control valve equipment is large, the capacity of the fuel tanks arranged at left and right sides of the vehicle body frame cannot be increased.
To detach the valves from the control valve equipment so as to maintain or exchange the valves, it is necessary to remove the control valve equipment from the vehicle body frame temporarily so as to take out the valves disposed inside. This work is troublesome because the fuel tanks are arranged at left and right sides of the vehicle body frame. Even if the valves are disposed on the side surface of the control valve equipment and along the lateral direction of the vehicle body frame, it is not easy to remove the valves.
Moreover, the control valve equipment disclosed in Patent Literatures 2 and 3 is arranged by providing an opening in the side wall of the vehicle body frame. Accordingly, the production process becomes complex so as to form the opening separately, thereby improving the production cost.
Patent Literature 1: the Japanese Patent Laid Open Gazette 2003-94970Patent Literature 2: the Japanese Patent Laid Open Gazette Hei.8-156620Patent Literature 3: the Japanese Patent Laid Open Gazette Hei.8-277802